When cardiac muscle cells are damaged by a heart attack, they are usually replaced by new cardiac muscle cells. new smooth muscle cells. connective tissue cells. epithelial cells. nerve cells?

The correct answer is the connective tissue cells.

Explanation:

The heart does not possess the tendency to reproduce heart muscle after a heart attack and the lost cardiac muscle gets substituted by the scar tissue. The scar tissue does not donate to the cardiac contractile force and the left viable cardiac muscle is vulnerable to greater hemodynamic burden.  

With time the muscles of the heart ultimately fail to result in the development of heart failure. The scar tissue, as the component of the healing procedure are the unique cells known as the fibroblasts. They are the fibrous connective tissue formed of collagen.  

velocity and height

it's anything that aren't producers and consumers.

explanation:

you've got to be clear on what "this" is